I. Field of the Invention
The invention generally relates to an apparatus and method for providing infrastructure in a wireless communication system. More particularly, the invention relates to an IP-based (Internet Protocol-based) cdma2000 base station.
II. Background
Wireless communications systems are widely deployed to provide various types of communication such as voice, data, packet data, and so on. These systems may be multiple access systems capable of supporting communication with multiple users sequentially or simultaneously by sharing the available system resources. Examples of such multiple access systems include code division multiple access (CDMA), time division multiple access (TDMA), orthogonal frequency division multiplexing (OFDM), and orthogonal frequency division multiple access systems (OFDMA).
The hardware used for infrastructure support for wireless systems are typically dedicated for the given system. For example, a CDMA2000-1x based infrastructure comprises CDMA 2000 1x Base Station Transceiver Subsystems (BTSs) and Base Station Controlloers (BSCs), a CDMA2000-1xEVDO (also known as High Data Rate, or HDR) based infrastructure comprises CDMA-1xEVDO BTSs and BSCs, and a Global System for Mobile Communications (GSM) based infrastructure comprises GSM BTSs and BSCs.
For wireless providers, having to provide dedicated hardware for each different multiple access system is an expensive and somewhat hardware-redundant proposition. For example, traditional infrastructure design in k sectors over m types of air interfaces and n bands requires the use of k×m×n RF modules. This is especially true in so called “hot-spots”, or areas having a high concentration of users. Also, coverage in buildings is traditionally somewhat spotty, as the building itself leads to interference with infrastructure equipment. Further, there are frequently space limitations in hot spots or in buildings.
Synchronous wireless access systems, such as CDMA (IS-95 and IS-2000) require accurate time and frequency references at each BTS. In traditional infrastructure systems, each BTS has a dedicated global positioning system (GPS) time/frequency server to provide such time and frequency information to the BTS. Providing a dedicated GPS server contributes to significant cost infrastructure costs and potentially redundant resources, particularly within confined areas, buildings or other hotspots.
Traditional cdma2000(base stations are connected to the core network via standard circuit switched protocols (defined in the IOS specifications—TIA/EIA-2001), which are transported over framed-T1 lines.